Vulnerability in Go standard library net/http

[ Description ]Official description

When an HTTP server handler sends a 2xx response to an HTTP/1 CONNECT request and returns without hijacking the connection, the server improperly continues to read and serve requests from the connection. Since a 2xx response to an HTTP/1 CONNECT converts the connection into a tunnel, the server should not treat the connection as continuing to contain HTTP. The impact of this misbehavior is mostly limited to potential request smuggling, where an intermediate proxy considers the data on the connection to be tunneled and the server considers it to be HTTP.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ Advisories ]Government CERT advisories

• BSI CERT-Bund8 Oct 2026WID-SEC-2026-3841

  Golang Go: Multiple vulnerabilities Translated from German

  Risk mediumCVE-2026-94439CVE-2026-56866CVE-2026-94447+12 more CVEs

[ References ]References

• go.dev/cl/847311
• go.dev/issue/81744
• groups.google.com/g/golang-announce/c/U2fTuyDJznI
• pkg.go.dev/vuln/GO-2026-6613